To Editor Paulo Carvalho

Dear Editor

First of all, I would like to thanks you on your rapid and precise and helpful answer.

Here I send to you List of changes according to Reviewer#5 and Reviewer#6 from May 9th 2016.

For article MCRE-D-15-00899_R2 And title

Ferrocenyl chalcones with O-alkylated vanillins: synthesis, spectral characterization, microbiological evaluation and single crystal X-ray analysis

In corrected manuscript we accept suggestion of the Reviewers and reorganized data in manuscript in accordance with instructions. We also checked and corrected some minor typos, as well as data for our article previously under review, now accepted for publication. List of suggested changes and other observed incorrect words/formats are bellow.

All references and data herein were checked and corrected according to Instructions

We accepted new suggestions from Reviewer except suggestion of Review#6 that we should synthesize some new compounds and explore their structure-activity relationships. To be able to determine the relationship between molecular structure and antimicrobial activity, the value for results of antimicrobial activity should be presented as IC50 value for each component against each microorganism separately. In this method which we used to determine antimicrobial activity, results are expressed as MIC values. Determination of IC50 require different method of measurement. Synthesis of some novel compounds requires more efforts and additional time, since some of described methods isn’t dependent upon us, and we are not able to introduce additional new compounds and test it in accordance with Review#6 requests and include it into our article.

Dr Zoran Ratković,

Faculty of Science, University of Kragujevac

Reviewer #5: In this manuscript, the authors reported the synthesis, spectral, analytical, single crystal X-ray characterization and in vitro microbiological activity of a series of ferrocenyl chalcones, and they found out that some of the organometallic derivatives show noticeable activity toward different strains of bacteria and fungi. These results may be important for the development of new antimicrobial compounds. However, a major revision should be needed for the authors if they want to make this paper more convincing.

--1. In the abstract, it would be better if the authors can highlight the new compounds and how many new compounds they synthesized as well as the most potent compound toward different strains of bacteria and fungi in this manuscript.

** Accepted and included in Abstract

--2. Page 20, Line 347-348, the authors wrote "compared with our compounds standard antibiotics, streptomycin (for bacteria) and ketoconazole (for fungi) showed slightly stronger activity" Obviously, this conclusion was not consistent with the antibacterial activity dates they obtained or even wrong. From the results shown in Table 4 and Table 5, we can see most of the compounds just showed very weak antibacterial activities or antifungal activities while standard antibiotics showed very strong activities towards all of the bacterias and fungis.

** Changed explanation of activity

--3. As for the results of antibacterial and antifungal activities, the authors failed to mention how many times the tests were carried out for each of the sample, one time, two times (duplicate), or three times?

** In experimental section for antimicrobial activity we added comment that experiment was carried out in triplicate.

--4. Page 7-page 9, all of the frequencies of NMR (MHz) and D-solvents are missing, it is suggested the authors add this information.